This invention relates to a gravure press, in particular for indirect gravure printing using a silicon rubber pad which is first pressed upon the inked and wiped gravure plate to absorb ink and then pressed upon the material to be printed, where all the ink is completely transferred due to the somewhat ink-repellent character of the pad surface, comprising a mounting plate for a gravure plate having a top coat of a light-sensitive plastic applied to a plastic film serving as substrate, further an inking device for applying ink to the plate which has an engraving depth of approx. 10 to 40.mu., a doctor blade for wiping the inked plate, and a drive mechanism for the silicon rubber pad, the inking device and the doctor blade.
In this known printing process which is particularly suited also for printing curved surfaces and which offers the advantage that inks can be applied to provide good coverage, gravure plates of hardened steel are preferably used. These plates are engraved or etched, mostly line-etched. Depending on the subjects to be printed, the etching or engraving depth vary between 10.mu. and 40.mu.. However, the production of steel plates is extremely expensive. Instead of steel, zinc, copper, brass and even glass are used as materials for the plates. However, the production of these plates is expensive and complicated, and in addition highly toxic waste products are obtained in the production of these plates.
There have also been known plastic plates in which the individual halftone dots take the form of cup-shaped recesses which contours of circular cross-section. The quantity of ink retained during the wiping process in these recesses depends on the etching and washing depths. If well covered surfaces are to be obtained, neighbouring dots must run into each other during the printing operation. This is favored by the fact that the edge of the cup-shaped recesses is inclined in relation to the surface fo the gravure plate so that the material to be printed, which must however not be rigid but at least as resilient as paper, absorbs the ink from the cups. On the other hand, however, it is an undesired effect of these inclined edges that no sharp contours can be obtained because the ink tends to flow at the edges. In contrast, the printing method using a steel plate permits the use of relatively steep-walled line etchings so that prints with sharp contours can be obtained. The silicon rubber pad absorbs the ink under pressure from these recesses and transfers it to the material to be printed, which may also be completely rigid. As the ink does not run on the silicone rubber pad, printings of microscopic sharpness are obtained, and the coverage is also of a perfection which can otherwise be obtained only by screen printing.
Now, it is the object of the present invention to provide a gravure press using a gravure plate for printing which can be produced at considerably lower cost than the known plates, which will give good printing results and have a satisfactory service life in spite of the stresses to which it is subjected by the wiping process.